Axial type fluid power unit



April 17, 19451 2, D, RUBEN 2,549,711

AXIAL TYPE FLUID POWER UNIT Filed May 8, 1948 4 Sheets-Sheet l FIGI883iL 8 l NVE N'I'OR.

Zorro D. Ruben April 17, 1951 Filed May 8, 1948 z. D. RMBEN A'xrAL TYPEFLUID POWER UNIT FIG. 3

4 Sheets-Sheet 2 /NrEN'l-ole, Zorro D. Ruben April 17, 1951 z. D. RUBEN2,549,711

AXIAL TYPE FLUID POWER UNIT Filed May 8, 1948 4 Sheets-Sheet 3 FIG. 9

[NVE N'I'OR.

Zorro D. Ruben April 17, 1951 z. D. RUBEN 2,549,711

ftp-"s Patented Apr. 17, 1951 UNITED l STATES PATENT oFFicE 2,549,711 lY AXI'AL TYPEFLUID POWER UNIT t Zorro D. Ruben, Tucson, Ariz. I YApplication May s, 1948, serialrNo. 25,943 Y 13 Claims.

rotating parts. These are often termed axial or axial cam mechanismsbecause they include pistons which are arranged with their vaxesparallel to andspaced around a central axis, and their motion isconveyed'to or from an axial cam. The cam may be of the swash plate typeor wobble type, or a combination of the two. Advantages o f thisarrangement include compactness and reduction of weight for a givenpiston load. Specifically the invention is applicable to mechanisms ofmotors or lpumps for liquids or gases and to heat engines and powertransmission machines. e

It is an object of the inventionpto provide a motor andpump mechanism ofthe axial type in which the thrust reaction on a piston is substantiallyparallel to and coincident with the piston axis', ;and to accomplishthis .without the employment of yoke members that slide back and forthwith varying velocity and pressure against a bearing alongside thecylinder. Thus, the cylinder may be exposed 'for cooling purposes alongpractically its entire length, and an undesirable type of friction willbe avoided.

It is a still further object of the invention to accomplish the aboveand other improvements .with parts involving reduced friction losses andmaximum sustaining power for their dimensions.

"hus, rolling contact may be provided between bearing parts or thrustand journal bearings, .rather than oscillating members. Notably, theuniversally jointed vconnecting rod link is' eliminated, and a simplerand more durable arrangement is substituted therefor, which also servesto hold the cylinder block and wobbler against continuous rotation withrespect to each other with- ,out vthe formerly required universal jointlinkage or trunnion support.

v It is al still further object of the present in- -vention to providean axial cam type mechanism for the interconversion of rotary andreciprocatling'motion which is so constructed as to enable theutilization of a relatively large cam angle.

Axial cam mechanisms asheretofore constructed have involved kinematicproblems which were compromised by limiting the angle of .inclinationVof the cam. This results in relatively short stroke designs withproportionally high friction losses.

In accordance with the principles of the present invention manyheretofore existing kinematic compromises have been eliminated and otherstructural features introduced to enable the employment of a relativelylarge cam angle and stroke.

In an axial cam mechanism in which each piston bears directly orindirectly on an inclined surface, the locus of the intersection betweenthe surface and the longitudinal center line of the piston is anellipse. This has heretofore necessitated theprovision of means fortransmitting the thrust between a cam surface or wobbler and the pistonthrough some intermediate member which is in slidable relationship tothe wobbler or cam and the piston, or to both. The sliding is in amountsand directions required to compensate for the differences between themajor and minor axes of the ellipse. I have discovered that it ispossible to actuate the center of piston thrust or thrust point on awobble plate in'such a manner that its locus with respect to the wobbleplate is a circle and its locus asprojected onto a plane atright anglesto thel piston axes is also a circle which is coincident with the pathof travel of the pistonaxes. When viewed in relation to the axis aboutwhich the wobble plate rotates, my new designprovides for locating thethrust pointl on a rotary intermediate bearing member that is Amountedon the rotatable wobble plate.V The vand direction that the resultingmotion of the thrust point of the intermediate bearing member will beelliptical, the ellipse being coincident with the ellipse that resultsfrom the projection of the piston axes onto the wobble plate as thepiston axes are rotated.

It is a further object of the present invention Yto provide an axial cammechanism of the above mentioned character wherein the bearing surfacebetween the intermediate bearing member and the plate on which it isrotatably mounted is :a surface of revolution, preferably a conicalsurface. The cone thrust bearing has the advantage of reducingfrictional loss as it combines the lthrust and radial components intoone bearing surface.

It. is a still `further object of the present invention to provide anaxial cam mechanism of the above mentioned character with means forassuring continuous lubrication of the bearing surfaces of theintermediate bearing member as the mechanism operates. This result isobtained, in the preferred embodiment of the present invention, byhaving oil ducts extending to the conical bearing surface from thecenter of rotation of the wobble plate or other member that supports theintermediate bearing member so that lubricating oil is forced to theconical bearing surfaces by centrifugal action of the mechanism as themechanism rotates.

It is a still further obj ect of the present invention to provide a pumpmechanism of the above mentioned character wherein the piston stroke ismaintained constant and the output per stroke is varied by varying theclosure and opening of -l the intake and discharge ports in relation tothe positions of the pistons. ln the preferred embodirnent of thepresent invention the cylinder block rotates as the pistons reciprocate.The

block rotates about an angularly adjustable stationary central memberwhich has passageways formed therein that constitute the intake andoutlet ports. These passages come into contact with one or the other ofa set of ports on each cylinder bore as the cylinder block is rotated.By changing the angular position of the central member the relationshipbetween the time of opening and closing of the ports and the positionsof the pistons is varied to vary the output of the pump. When this samemechanism is used as a hydraulic motor the same adjustment is effectiveto change the speed of the driving part of the motor.

l The attainment of the above and further objects of the presentinvention will be apparent from the following specification taken inoonjunction with the accompanying drawings forming a part thereof.

In the drawings:

Figure l is a longitudinal sectional View through an axial type oil pumpembodying the present invention;

Figure 2 is a sectional View taken along the Vline 2-2 of Figure 1 andlooking in the direction of the arrows;

Figure 3 is an enlarged sectional View of a portion of Figure l;

Figure 4 is a fragmentary View showing the oil grooves on the conesurface;

Figure 5 is a diagrammatic view of the center lines'of the drivingmechanism;

Figure 6 is a sectional View taken along the line 6 6 of Figure 1 andlooking in the direction 'of the arrows;

Figure 7 is a sectional view taken along the line '-l of Figure 1 andlooking in the direction of the. arrows;

Figure 8 is a section taken along the line 8-8 of Figure 1' and lookingin the direction of the arrows;

Figure 9 is a longitudinal sectional View illustrating a modifiedconstruction; and

Figure 10 is a sectional View taken along the line l-ill of Figure 9 andlooking in the direction of the arrows.

Reference may now be had more particularly to the drawings wherein likereference numerals designate like partsV throughout.

The structure illustrated in Figure l is a high pressure oil pump,although the same structure may constitute a hydraulic motor. The pumpis indicated in general by the reference numeral I and includes astationary housing 2, circular in cross section, said housing comprisingtwo parts, indicated at 3 and 4', suitably bolted to- Cil gether. Thepart 4 may be mounted in any desired manner on a prime mover, or on adriven machine to which the rotatable drive shaft 5 may be connected.Means for ingress and egress of liquid or gases may be of anyconventional type, one preferred variable delivery type being hereillustrated. Y

A drive shaft 5 is centered in the housing part i as, for instance, bysuitable sets of ball bearings, one of which is a thrust bearing forholding the shaft against longitudinal movement. A suitable liquid sealis provided where the drive shaft 5 leaves the housing part 4. Thelongitudinal center line of the drive shaft is indicated by the centerline E which is the axis of rotation of the shaft.

A stationary spur gear I0 is centered around the drive shaft 5 andsecured to the housing 4 as, for instance, by being brazed to an annularplate II that is mounted on the inner face of the housing part 4 by aseries of screws or the like I3 and located radially by a dowel pin I2.An eight armed plate I5, which corresponds functionally to a wobbleplate, is integral with or secured to the drive shaft 5 and is centeredthereon and extends at right angles thereto. Four idler gears I? aremounted on the'plate I5 for rotation about axes fixed with respect tothe plate and parallel to the axis of rotation of the drive shaft 5.These idlers are'in mesh with the teeth on the spur gear IU, as may beseen from Figure 2, and each idler is in turn also in mesh with a pairof spur gears I8. Each spur gear I8 is of a pitch diameter exactly halfof thepitch diameter of the gear I so that each spur gear i8 istherefore rotated about its center at an angular speed twice that of theshaft 5.

Each spur gear I8 is keyed to an intermediate bearing member 20 that isrotatably mounted on the plate I5 on the'face thereof opposite the facewhere the gear I8 is located. Each intermediate bearing member 2B has aconical bearing surface that fits into a similar conical shaped openingin the plate i5 for receiving the' thrust between the intermediatebearing member and the plate l5.V Each intermediate bearing meme ber'also has a short stem 2l; circular in cross section, that ts through acorrespondingly shaped hole in the plate I5 in which the stern 2l isfree to turn. The axis of rotation of the intermediate bearing member 2Ein the plate I5 is indicated by the center line 22 which is parallel tothe axis of rotation 6 of the drive shaft 5. Each intermediate bearingmember 26 is provided With a socket 23 of a shape conforming to aportion ofthe surface of a sphere centered at the point 2li. The center24 is eccentric with respect to the axis of rotation 22k of theintermediate bearing member 28 in the plate I5. The location of thiscenter point 211 and the reason therefor will be more fully set forth asthis description proceeds. It is sufficient here to state that thecenter points 24 of each of the eight intermediate bearing members 28vall lie in the same plane, which is a plane perpendicular to the centerline G, and to state that the center lines 2'2 of eachof the eightintermediate bearing members are at the same distances from the centerline S, and that all of the intermediate bearing members 28 are ofexactly the same construction.

The plate I5 has a series of oil ducts 26 therein each leading from thecenterof the plate member I5 to one of the intermediate bearing memberswherebyy lubricating oil in the housing' 2'fwill1be 5;,- forced bycentrifugal action through the ducts 26 for lubricating the bearingsurfaces between the respective intermediate bearing members v20 and theplate I5. To facilitate the lubricating action each intermediate bearingmember has on the conical surface thereof a series of oil grooves 21, asmay be seen from Figure 4. The sides of the oil grooves may be roundedto faciltatev formation of a wedge-shaped film of lubrieating oilbetween the conical surface of the intermediate member and the member 5.By providing for the continuous flow of fresh lubricating oil a higherrubbing Velocity may be maintained between the intermediate bearingmember and the member I5 than would otherwise be possible.

Within the housing part 3 there is mounted a cylinder block 30. Thecylinder block is Vrotatably mounted on a pintle valve 3| that is lockedin angularly adjustable position in the housing threaded `shank 33integral therewith for receiv.-

ing a threaded cylinder block holding nut 3B that is locked in place bya lock nut 34, to hold the cylinder block against movement axially ofthe pintle valve 3l while permitting the cylinder block 30 completefreedom of rotation around the pintle valve 3I along the conical surfacethereof. The cylinder block 3| is thus rotatable about the pintle Valve3|, the axis of rotation being indicated by the line 31. It is to benoted at this point that the axis of rotation 31 intersects the axis ofrotation 6 and that the point of intersection lies inthe planedetermined by the centers 24 of the eight intermediate bearing members.

The cylinder block has eight cylinder bores 38 therein. The longitudinalaxes of the respective cylinder bores are all parallel to and uniformlyspaced around the longitudinal center line 31. Within each cylinder borethereis an elongated piston 39 that is freely reciprocable therein. Eachpiston 39 has'at its outer end a short stem 40 that terminates in a ball4I, the ball 4I being in turn spun into a ball socket 42 of theintermediate bearing member forming a common ballr and socket joint. Thestem 40 affords a small amount of flexibility between the piston and theball 4I. Asmay be seen from Figure 3, the center of the ball 4Ijnecessarily coincides with the center of the socket 22, and the centerline of ber I5 to rotate, and causes the axis of rotation 22 of the gearI8 to rotate about the center 6. At the same time the gear I8 is rotatedabout its axisof rotation 22 at an angular speed exactly twice the speedof the shaft 5. This causes the eccentric point 24 to rotate withrespect to the plate I5 about the axis 22 and to rotate with the plateabout the axis 6. The eccentric point 24 moves in a plane, which isindicated inFigure 5 by the reference numeral 45. All of therespecv-tive points 24 move in the same plane.

rIn View of the fact that the balls of the respec- Mtive pistons arealsocentered at 24 and are held in the sockets of they intermediate bearingvmembers, it follows that the centers of the balls 'IIV .will also moveAin the plane 45.( A forcelfwill thus be Vtransmitted through the balland socket connections and the pistons', through the walls of thecylinder bores 38 to the cylinder block 30 causing that block to rotate.Since that'block rotates about the axis 31 which is inclined to the axis6 it follows that the locus of the centers of the balls 4I in the plane45 must be an ellipse. The minor axis of the ellipse is 2r, where r isthe distance between the center of the ball 4I and the axis of rotation31. kThe major axis of the ellipse is 2r .divided by the cosine of theangle A between the axis 31 and the axis 5.

In order to permit operation of the structure thus far described it isessential that the locus of the center point 4v of the intermediatebearing member as determinedby the rotation of the intermediate bearingmember 2E) by the gear I8 on the rotating plate-I5 shall be exactly thesame as that of the ellipse above set forth. r)This result is obtainedby adhering to the following relationships, reference being had toFigure 5: The eccentricity e represented by the distance'between thecenter line 22 and the center 24 is made equal to one-fourthV the`difference between the major axis and the minor axis of the ellipse asset forth-above, and L is the distance between thekcenter line B and thecenter line 22. Since e is made equal to Mr of the difference betweenthe major and minor axes ofthe ellipse, as set forth above, and sincethe minor axis of that e1- lipse is 2r and the major axis is cos A itfollows that four times e will equal the difference between the twoaxes, or:

2r 2ML-cos A) 1 4e*cos A 2T- cos A T(l-cos A) 2 5'*- 2 cos A also v y 3L major axis e 271 T(l-cos A) 2A 2 cos A 2 cosA l-I-cos A 4 LT( 2 cos AFrom the above equations it also follows that y (1-I-cos A) r(l-cos A) 5L e-T 2 cos A 2 cos A y ((l-I-cosfD-(l-cos A)) 7' cos A (2 cos A) 7 LVe-r- 2 COS A -r 8 L=rle and e=Lr From Equation 4 it follows that:

9 L(2 cos l-I-cos A Substituting this value of r in Equation 2 we get:

10k L(2 cos A) l-cosA I el-l-cosAl 2 cos A L(l-cos A) l l-I-cosA lanellipse of exactly the same major and minor axes as the ellipse formedby the intersection of 7 the piston center line 43 with the plane 45 asthe piston center line 43 is rotated about the cylinder block 3l aboveset forth. A

To bring the two ellipses into coincidence the member 2) is initiallypositioned so that when its center 25a is in the plane determined by thecenter lines 8 and the point 2A is also in that plane and at a distanceL-l-e from the axis 6. From this position the trace of the point 25resulting from the rotation of the member I5 and the intermediatebearing member 2i) will coincide with the ellipse formed by theintersection of the center line 553 With the plane 65 asthe cylinder'block rotates about its axis 3l. Rotation of the shaft 5 will result inreciprocation of the piston 3S in the cylinder bores and rotation of thecylinder block about the axis 3l.

The cone surface of the intermediate bearing member 23 combines thethrust and radial components Withrespect to the axis 6 of the pressurebetween the ball lll and the socket 23 in one bearing surface. Thisresults in a substantial reduction in the friction loss as compared tothe friction losses that would result if the intermediate bearing memberwere provided with different surfaces which would take, respectively,the thrust and the radial components of the load. During operation oi"the mechanism the housing 2 contains a mass of lubricating oil to alevel above the center line 6 thereof. As the plate I5 rotates it willcause oil to now by centrifugal action from a central opening 48 thereinthrough the oil ducts 2e to the bearing surfaces between theintermediate bearing member and the plate l5.

The present arrangement as above described makes possible a rotary axialpiston pump or motor wherein the angle A between the center line 6 ofthe plate l5 and the center line 3l of the cylinder block may be of theorder of 45, thus resulting in a large piston stroke, that is, av pistonstroke of a length equal to the piston circle diameter. The primaryadvantage of a large stroke is that there is a greater pump output perrevolution of the mechanism and therefore the friction losses perrevolution bear a smaller relationship to the total output than would bethe case if the output were less.

An explanation will now be given of the valve arrangement of the pumpwhereby the displacement of the pump may be varied from zero to fullload even while the pump is operating. As previously stated, the pintlevalve 3| supports the cylinder block at the conical surface 32 thereofwhich makes a snug sliding nt in the cylinder block. The pintle valvehas an intake port 69 and a discharge port 6| each formed by a slot cutinto the conical surface. The slot 6i! terminates at 52 and the slot 6|terminates at 63, as shown in Figure 8. Intake and dischargepassagevvays i311 and 65 are drilled axially in the pintle valve, theirtops being closed by'- plugs 66 and 6l', and they communicate betweenthe ports E0 and 6| and radial ports E9 and il), respectively. Theradial ports G9 and 'lll consist of slots formed, in the pintle valve,and they communicate with an intake port il and a discharge port 12,respectively, which are o'ri'n-ed in the casing part 3. ri`he pintlevalve includes a dat circular shoulder 'l5 that is adapted to rest on ashoulder l5 in the housing part S, and it is held locked in its'angularly adjustable position by` a take-up nut l@ and` a replaceablewear plate E91 A handle 8B 8 pintle valve. A set screw 82 acts on a plug83 which ts the threads of the take-up nut and serves to lock thetake-up nut in pintle valve holding position.

The cylinder block 30 has intake ports 85 and discharge ports 86 leadingto the respective cylin der bores 38. The intake ports 85 communicatewith the intake port 60 of the pintle valve during half of eachrevolution of the cylinder block around the pintle valve, and thedischarge ports 86 .in the cylinder block communicate with the dischargeport 6| through half of the revolution of the cylinder block around thevalve. This may be'. seen from Figure 6. In Figure 6 it is assumed thatthe cylinder block 3 is rotating counterclockwise. At this time theintake port 85 of the cylinder bore C1 has just been closed fromcommunication With the'discharge port 6| and iS about to be brought intocommunication with the intake port 6] in the pintle valve. At the sametime the cylinder bore Cs has just been closed from communication withthe intake port 60 and is about to be opened into communication with thedischarge port tl in the pintle valve. At that time the cylinder boresC2, C3 and C4 have their intake ports 85 in communication With theintake port 66 and the cylinder bores Ce, C7' and Ce have their intakeports 85 closed from the intake port 6G. Those cylinder bores whoseintake ports' are in communication with the intake port 6U have theirdischarge ports closed from communication lwith the discharge port 6I,and those cylinder bores Whose intake ports are closed fromcommunication with the intake port 60 have their' discharge ports 86 incommunication with the discharge port 6|, except for the two cylinderbores that are momentarily in the position indicated by the cylinderbores C1 and C5 Whose ports are closed from communication with eitherthe intake or the discharge ports,

By adjusting the angular position of the han- Ydie 8G it is possible tochange the timing of the opening and closing of the inlet and dischargeports in relation to' the positions of the pistons in the cylinder boresand their directions or movement, thus changing the output of thept-imp. The net effect will be an interficw of fluid 'among thecylinders and a reduced external flow. By this meansl the output of thepump can be reduced to zero by a 90 rotation of the handle.

The cylinder block may be hydraulically balanced on the pintle valve 3|by providing a duct se leading from the discharge port 65 to theperiphery of the pintle valve Where it communi- Cates with an annulargroove 9| in the cylinder block.

Reference may now be had to Figures 9 and l() showing a modifiedconstruction. The pump or motor' illustrated in Figure 9' comprises astationary housing lill, circular in cross section, which may be mountedin any desired manner to a prime mover or to a driven machine to whichthe rotation shaft |02 may bev connected. Means for ingress and egressof fluid or gases are not detailed, inasmuch as they can be of anyvcustomary' construction, such as, for example, that shown inmy PatentNo. 2,498,451-, which is of the ported cover plate type. The shaft |02is centered in the housing and is keyed to a cylinder block HB3r bysplines |06. The cylinder block contains a plurality of pistons |94'operating in bores parallel to the shaft W2; vThe longitudinal centerlines of the pistons are ind'icated by the center lines |05, which arespaced from-the'- axis of rotation |01- of theshaft |92 a axisl H4.

shaft axis |071` at a point O- adistance h from the bearing surface |I3.The wobbler axis I|4 and `distancerv as indicated. The cylinder block isprovided with a bore |08 housing a radial bearingy |09V supported on ashort spindle projection of an axial cam III which is bolted to thehousing |0| by means of bolts ||2.

The axial cam| is provided with abearing vsurface v|.|3 which isperpendicular to a wobbler The wobbler axis ||4 intersects the the shaftaxis |01 are inclined to each other at lan angle A as shown. .A helicalspring ||5 is mounted against a shoulder I I'! about the spindle I I 0and bears against the bearing` |00, which transmits a force to thecylinder block |03, tending tomaintain it in pressure contact with theported end of the housing |0| Itisthus far apparent that the shaft |02can l be usedy tov rotate or be rotated by the cylinder block `|03 aboutthe shaft axis |01, which coincides with the axis of the spindle IIE).Opposing the cylinder block is-.a bearing surface I I3, makcam.A

Secured to lthe cylinder block |03 by a key I I8 is a bevelgear IISrotatable with respect to the shaft axis |02! as is vthe cylinder block|03, having its cone centerv or vertex at the point O. The bevel gear I|9 yengages a like bevel'gear |20 having vits cone center coincidingwith that of the' gear IIS at point O and rotatable about the wobbleraxis H4. The bevel gear is secured to the wobbler |2| as by screws |22.VThe wobbler |2| is provided with a central bore I2?1 providing a radialbearing on a journal section |24 of the cam III centered on the wobbleraxis |14. 'Thus 'the wobbler is free to rotate about the wobbler axis II4, supported by a, journal integral with the cam and is keyed, by theengagement of the bevel gears I9 and |20, against rotation with respectto the cylinder block |03.

Radially spaced a distance L from the center` l of the wobbler boreV |23are circular bearing bores |25 pla-ced in the` wobbler vwith theircenters at angular spacings to correspond with that of the pistons inthecylinder block. Bores |25varede that of the gearsA |29, and is providedwith twice the number of teeth. It is thus apparent that as the wobbler|2| rotates on the journal |24, the

sun'gear |30 vdrives the gears |29 in their bearings |25 at twice theangular shaft velocity.

Each bushing |28 is provided with a bore |33 which is eccentric withrespect to the center of minatesin a slipper '|38A which bears againstthe vparallel to the wobbler axis II4.

.adjacent slippers vand parts.

l() axial'cam surface H3. The journal section |34 is drilled andtappedto receive a retainerV |39 which is swaged 4on the spherical back|40 of the plane piston end |37. Retainers |39 remain with the pistonsand are assembled to the jour? nal sections |34 after these have beenplaced in assembly Vwith the bushings |28, the wobbler |2| and thewobbler journal |24. Interposed bearing member |35 comprises threeessential thrust communication bearing .surfaces and'one piston returnsurface.

A cone surface |4| is centered on an axis |42 The length of theinterposed bearing member |35, along the cone axis |42, from the conevertex |43 to the axial cambearing surface |,|3, is required to equalh.,which, as previously stated, is the `distance along the wobbler axis I4,from its intersectionwith the shaft axis |01 at point O, to the plane ofthe axial cam bearing surface I3. The

radial distance L, of the center line of bores` |25- in the wobbler, tothe wobbler axis II4, is required to bel equal to.

2 cosA lThe eccentricity eis required to be L-r.

The cone axes |42, as shown in Figure 9,'-ritersect thefpiston axes |05in av plane passed through the vertex O- at right angles to the -axis|||.v They are maintained in this plane of contact by the rotationimparted to the gears |29 by the sun gear |30 and theeccentricity of thebores |33 in the journals |2|'. v Thus, the cone |4I is maintained insuch position on the piston plane end |31 that pure rolling contactthrust transmission takes place. It is evident that the piston reactionis substantially'parallel to the piston axis although somewhat oifcenter.

The slipper |30, which is an integral part of the interposed bearingmember generally indi- .cated at |35, is an extended bearing surfacewhich preferably approaches the cam bearing surface I I3 and isseparated therefrom by a wedge shaped clearance space lubricated by anoil film. This may be conveniently accomplished by methods described inmy patent application Serial No. 530,416. The face of slipper |38,contacting bearing surface I I 3, is preferably of a kidney shape, togive a maximum bearing area, leaving'roorn for circumferential andVradial clearance of the It is thus evident that the cam surface ||3exerts a reaction, substantially parallel `tothe wobbler axis, to thepiston thrust. Thus the wobbler |2| must sustain the side thrustresulting from the two opposed forces which areV not in the same line.The resultantof all the piston side thrust forces may be' resolved into`a radial load on the cam jourr,ing gear teeth of bevel gears |I9 and|20.

In operation as a pump in theembodiment i shown in Figure 9 and Figure10, rotation' of the shaft |02 Vcauses the cylinder block |03 and thebevel gear I I9 affixed thereto to rotate.. Bevel gear I|9, engaging thelike gear |20, of equal number of gear teeth, causes bevel gear |20 torotate on the journal surface |24 about the Wobbler axis ||4. Bevel gear|20 being fixedto the and the interposed bearing member |35 in eachwobbler |2| which contains the gear bushing |29 the bore inthe wobbler|23 -is therefore desirl l able. This may be either of an ordinary oilnlm lubricated type or a roller bearing.

The wobbler assembly as described hereinabove, and generally indicatedby |36, rotates with respect to the sun gear |30 which is affixed to thestationary cam Thus the gears |29, engaging the pinions |29 which engagethe sun gear, and being one-half the pitch diameter in size, and havingone-half the number of teeth, rotate about their own centers, at twicethe angular velocity of the wobbler assembly about the wobbler axis, andin the opposite direction. The gear bushing |28, having bores |33therein, eccentric to the journal surfaces |21, which contain theinterposed bearings |35, the latter are also 1 given a motion ofrotation. They rotate about an axis parallel to the wobbler axis, spaceda distance L therefrom, and in a counter-clockwise direction when thewobbler rotates in a clockwise direction. The combination of thesecircular motions is such that the cone vertex |43 is stationary withrespect to the piston axis |05.

Thus the cone |4| maintains pure rolling contact with the piston planeend |31 as long as there is thrust transmission therebetween andV piston|04 is free to rotate at a relatively slow rate in its bore, and slipper|38 is restrained from rotation by contact of its inner edge |45 againstthe cam shoulder |45. It is apparent that bearings at journals |34 and|21 should vthrust, to the cam bearing surface HS, extends beyond thebore |25, and thus serves to withdraw or return the piston IM on asuction stroke by means of the spherical back |40, enclosed in theswaged retainer |39. Should some other means of piston return beprovided, the slipper |33.v

may be pivoted to the journal |34 of the interposed bearing member |35in the manner of a Michell pad.

An examination of the structures of Figure 1 and of Figure 9 showsclearly that although the members i5 of Figure 1 and |35 of Figure 9rotate about an axis at right angles to the members, they arenevertheless wobble plates with respect to their cylinder blocks,because during each revolution of operation of the structure thedistances between the outer end of each cylinder bore and the wobbleplates progressively increase from a minimum to a maximum and then backto its minimum value, the change being the same in the structure-ofFigure 1 as in the structure of Figure 9.V It is also apparent thatwhile in Figure 9 the rotative power is applied from the cylinder blockto the wobble plate, the reverse direction of power transmissionprevails in the structure of Figure 1, and that the force re quired toturn the cylinder block 3|) of Figure l about the pintle valve 3| ismerely that required to overcome the frictional resistance to motion ofthe cylindei` block about the pintle valve. This is of such a smallmagnitude that that force can` readily be transmitted through thepistons and the cylinder bores to the cylinder block. It is also to benoted that in the structure of Figure 9 each piston is connected to itsball socket through a comparatively slender piston rod. In t Figure 3the connection is through the short stem 40. In either event there issuficient flexibility in the stem 4|) or in the slender piston rod tocompensate for any mechanical errors, or deviation in the machiningoperations, so that a very slight discrepancy in the location of anycenter pointl 24 lof Figure 3 with respect to its associated piston, ordiscrepancy in the location of the point |43 of Figure 9 in relation tothe position of its associated pistonywill not prevent operation of thestructure.

In compliance with the requirements of the patent statutes I have hereshown and described a few preferred embodiments of my invention. It is,however, to be understood that, the invention is not limited to theprecise constructions here shown, the same being merely illustrative `ofthe principles of the invention. What I consider new and desire tosecure by Letters Patent is:

1. A motor or pump mechanism of the "axial type comprising an axial cam,a wobbler journalled on said axial cam, a cylinder block containing aplurality of parallel pistons disposed about a common shaft, each of thepistonster- Y minating in a plane surface perpendicular to the pistonaxis, means for transmitting thrust between each piston and the wobbler,said means comprising separate bearing members interposed between eachplane piston end and a curved suring members one surface having motionwith respect to the associated piston and the opposite lsurface havingmotion with respect to they wobbler, the first of said motions being arolling` motion and the other motion being a sliding motion, and meansto prevent rotation of the wobbler aboutl the shaft with respect to thecylinder block, comprising the engagement of a pair of equal bevelgears, one centered on the shaft axis, the other centered on the wobbleraxis, both having vertices at the intersection of said axes, the formerbeing affixed to the cylinder block and the latter to the wobbler.

2. In mechanism, a piston reciprocable within a cylinder block, spacedfrom, axially parallel and rotatable with respect to a shaft, an axialcam bearing surface perpendicular to a wobbler axis which intersects thevshaft axis at a point O, a wobbler with a radial bearing havinga bevelgear affixed thereto, both centered on the wobbler axis, said gearengaging an equal gear centered on the shaft axis and affixed to thecylinder block, said gears having common vertices at point O, a member,supported by the wobbler, in-

| terposed between the piston and the cam bearing surface, to transmitthrust forces therebetween in such manner that the piston reaction issubstantially parallel to the shaft axis, the cam reactionY issubstantially parallel to the wobbler `axis, and.

the kresulting side thrust is sustained by the radial bearing and theengaging gear teeth.

3. In combination, a cylinder block having pistons rotatable about theiraxes and parallel to a shaft and spaced from the axis thereof a distancer, an axial cam having a plane bearing surface perpendicular to awobbler axis which intersects the shaft axis at an angle A, a distance hfrom its bearing surface, said axial cam having a rotary motion withrespect to the cylnder block, a wobbler rotatably mounted on saidwobbler axis, means to prevent rotation of the wobbler with respect tothe cylinder block, a bearing member coating with each piston and ytheaxial cam bearing surface having, at the piston end, a surface ofrevolution centered on Aan axis parallel to the wobbler axis,`whichintersects the piston axis at a distancelh from the axial cam bearingsurface, each saidV bearing member being supported radially in aneccentric bore in a journal centered in the wobbler on an axis parallelto the wobbler axis and spaced therefrom a distance the amount of theeccentricity being e=L-r, and means of rotating each said journal tworevolutions for each revolution of the cylinder block with respect tothe axial cam so that pure rolling'contact thrust transmission occursbetween the piston and the bearing coacting with vabout the third axisat an angular speed twice that of the second member.

5. In combination a longitudinally reciprocating member, mounting meanstherefor rotatable about an axis of rotation parallel to and spaced fromthe longitudinal axis of the member, a second member rotatable about asecond axis of rotation intersecting the first axis and inclined theretoand also inclined to the normal thereto, means establishing a powertransmitting connection between the two members including a third memberrotatably mounted on the second member for rotation about a third axisof rotation spaced from the second axis of rotation, and means forrotating the third member about the `third axis at an angular speedtwice that of the second member and in a direction opposite to thedirection of rotation of the second member, the iirst and the thirdmembers being Yin thrust transmitting relation to one another and withthe center of contact between them located eccentric to the third axis.

6. In combination a longitudinally reciprocating member. mounting meanstherefor rotatable v about an axis of rotation parallel to and spacedfrom the longitudinal axis of the member, a second member rotatableabout a second axisof rotation intersecting the first axis and inclinedthereto and also inclined to the knormal thereto, means establishing apower transmitting connection between the two members including a thirdmember rotatably mounted on the second member for rotation about a thirdaxis of rotation spaced from the second axis of rotation, and means forrotating the third member about the third axis at an angular speed twicethat of of the second member and in a direction opposite to thedirection of rotation of the second member,

` the iirst and the third members being in thrust transmitting relationyto one another and with the center of contact between them locatedeccentric to the third axis and on a line extending at right angles tothe second axis of rotation at the point of intersection of the firstand second axes of rotation. f

7. In combination a longitudinally reciprocattion spaced from the secondaxis, and means for rotating the third member about the third axis at anangular speedtwice that of the secondy member and in a directionopposite to the direction of rotation of the second member, the firstand the third members being in thrust transmitting relation to oneanother and with the center of contact between them located eccentric tothe third axis and on a line extending at right angles to the secondaxis at the point of intersection of the first and second axes andfurthest from the second mentioned axis -of rotation .at the twopositions inthe rotation of the third axis about the second axis ofrotation when said center of contact intersects the plane determined bythe iirst and the second axes of rotation.

8. In combination a longitudinally reciprocatingmember, mounting meanstherefor rotatable about an axis of rotation parallel to and spaced fromthe longitudinal center line of the member, asecond member rotatableabout a second axis of rotation intersecting the first axis and finclined thereto and also inclined to the normal thereto, meansestablishing a power transmitting connecion between the two membersincluding a third member rotatably mounted on the second member forrotation about a third axis of rotation spaced from the second axis, andmeans for rotating the third member about the third axis at-an angularspeed twice that of the second member and in a direction opposite to thedirection of rotation of the 'second membenthe first and the thirdmembers being in thrust transmitting relation to one another and withthe center of contact between them located eccentric to the third axisand on a line extending at right angles to the second axis at the pointof intersection of the i-lrst and second axes and furthest kfrom thesecond mentioned axis of rotation at the two' positions in the rotationofV the third axis about the second axis of rotation when said where Ais the angle between the two first mentioned axes of rotation and L isthe distance between the second and third axes of rotation.

9. In combination a longitudinally reciprocating member, mounting meanstherefor rotatable about an axis of rotation parallel to and spaced fromthe longitudinal center of the member, a second member rotatable about asecond axis of rotation intersecting the rst axis and inclined theretoand also inclined to the normal thereto, means establishing a powertransmitting connection between the two members including a third memberrotatably mounted on the second member for rotation about a third axisof rotation spaced from the second axis, and means for rotating thethird member about the third axis, the

rst and the third members being in thrust transmitting relation to oneanother' and with the center of thrust located eccentric to the thirdaxis, the eccentricity e being L lcos A) C (l -l-cos A where A is theangle between the two first mentioned axes of rotation and L is thedistance between the second and third axes of rotation.

10. In combination a longitudinally reciprocating member, mounting meanstherefor rotatable about an axis of rotation parallel to and spaced fromthe longitudinal center of the member, a second member rotatable about asecond ,axis of rotation intersecting the first axis and inclinedthereto and also inclined to the normal thereto, means establishing apower transmitting connection between the two members including a thirdmember rotatably mounted on the second member for rotation about a thirdyaxis of rotation spaced from the second axis, and means for rotatingthe third member about the third axis at an angular speed twice that ofthe second member and in a direction opposite. to the I.direction ofrotation of the second member, the lirst and the third members being inthrust transmitting relation to one another and with the center ofthrust located eccentric to the third axis, the eccentricity e being l-cos A e-L l -i-cos A where A is the angle between the two firstmentioned axes of rotaion and L is the distance between the second andthird axes of rotation.

l1. In combination a longitudinally reciprocating piston, a cylinderbloclr in which the piston reciprocates, means for mounting the cylinderblock for rotation about an axis of rotation parallel to and spaced fromthe longitudinal center of the piston, a first member rotatable about asecond axis of rotation intersecting the rst axis and inclined theretoand also inclined to the normal thereto, means establishing a powertransmitting connection between the piston and the member including asecond member rotatably mounted on the nrst member for rotation about athird axis of rotation spaced from the second axis of rotation andparallel thereto, and means for rotating the second member about thethird axis at an angular speed twice that of the second member and in adirection opposite to the direction of rotation of the rst member, thepiston and the second member being in thrust transmitting relation toone another and with the center of contact between them locatedeccentric to the third axis and on a line extending at right angles tothe second axis Aof rotation at the point of intersection of the rst andsecond axes of rotation and furthest from the second mentioned axis ofrotation at the two positions in the rotation .of the third axis aboutthe second axis when said center of contact intersects the planedetermined by the rst and the second axes of rotation, the eccentricitye being Where A is the angle between the two rst mentioned axes ofrotation and L is the distance between the second and third axes. ofrotation.

12. In combination, two members mounted for rotation about respectiveintersecting axes making an acute angle to one another, a bearingmounted on one of the .members and receiving the thrust of the othermember, the center of thrust being in a plane which is normal to theaxis of said one member and which passes through the point ofintersecion of said axes, and gearing means for rotating said bearingwith respect to said one member about an axis eccentric with respect tothe center of `thrust, the eccentricitye being L l cos A) e m Where A isthe acute angle and L is the distance between the axis of rotation ofthe bearing and the axis of rotation of the member on which the bearingis mounted.

13. Mechanism including' a cylinder block having a reciprocable pistontherein, a wobble plate, and means for connecting the piston and thewobble plate for the transfer of power from one to the other comprisinga bearing member for transmitting the thrust between the piston and thewobble plate, said bearingmember being rotatabh7 supported by the wobbleplate, and gearing means for rotating the bearing member in the wobbleplate at the rate of one revolution per single stroke of the piston.

ZORRO D. RUBEN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 577,065 Pole Feb. 16, 1897646,658 Frazeur Apr. 3, 1900 1,800,929 Craig Apr. 14, 1931 1,842,322Hulsebos Jan. 19, 1932 2,337,821 Huber Dec. 2S, 1943 2,360,762` ConradOct. 27, 19,44

